Converter



March 19, 1935. T, A OHEN 1,994,635

CONVERTER Filed Dec. 25, 1932 Jayme Yfieadore Q. (b/2e74- [Patented Mar. 19, 1935 UNITED STATES CONVERTER Theodore A. Cohen, Chicago, Ill., assignor, by direct and meane assignments, of one-third to Wheelco Vacuum Products Company, Chicago, Ill., a corporation of Illinois, andtwo-thirds to Henry Jay Stephens, Chicago, Ill.

Applicfation December 23, 1932, Serial No. 648,537

The present invention has to do with a device for converting electrical energy from one form to another and relates particularly to a device adapted to provide, from a source of electrical energy of either constant or alternating potential, a source of energy of difi'erent potential.

An object of the present invention is the provision of simple means adapted to produce a source of alternating current from an energy source of directcurrent.

Another object of the present invention is to provide a novel device capable of. transforming energy from-a sourceof constant potential to a source of energy having an alternating potential of the same or of a diil'erent magnitude.

Still another object .of the present invention is the provision of a device adapted to convert electrical energy of constant potential into energy of alternating potential, the converted energy being of the same or. different potential as the original energy, and a constant frequency, as desired.

The above objects and other desirable objects will be made apparent in the following description which is to be read conjointly withthe accomp yins sheet of drawings hereby made a part of this specification, and in which:

Figure 1 is an orthographic projection of a form of the-invention taken from one side;

Figure 2 is a tic representation of the form of the invention shown in Figure 1.

Like reference characters will be used in the drawing and throughout the following description to designate similar parts.

In the figures there is shown an iron core 10. In Figure 1 the core is of the two window type,

there being an air gap 11 in the upper of the two windows 12 and 13. No attempt has been made to make the core, as it is schematically illustratedinl'igure'2,toappearasitdoesin Figure 1 because the exact path followed by the magnetic flux therein is immaterial.

About the central leg of the core 10 is a spool 14 having thereon a secondary coil 15, and two primary coils 16 and 17. Coil 17 has, effectively, twice the number of turns as coil 16, i. e., coil 17 is designed to produce twice the number of ampere'turns as coils 16. At the top of leg 18 of the core 10 is a non-magnetic post 19 which will usually be of a dielectric material. Any standard means 20 may be used to secure the post firmly to the core. Depending horizontally from the post 19 .is a vibrator member 21, there being a set screwf22 for anchoring said member in place.

At the extended end of the member-21 is a weight 23 that may a; adjustable longmidimuy of the vertically along with an adjustment screw 31 in incident to becoming heated tocarry the con-- member for changing the vibrating period thereof. Two separate iron cores 24 and 25 carry magnetizing coils 26 and 2'7 and the iron bar 28 at the under side of the vibrating member 21, all of which parts being disposed to move with the vi- 5 brating member. On the upper side of the member 21 is a contactor 29, which may be of platinum, and above and complementary to this is a similar contactor 30, the latter being adjustable 10 which it is mounted.

By making the vibrator member 21 of two metal strips of different coeillcients of expansion, and with the metal having the lesser coefiicient nearest to contactor 30, the period of the member 21 can be made constant despite a change in temperature thereof and a corresponding change in overall length. When the member 21 is bimetallic and is of the design stated it will curl cotactor 29 nearer to contactor 30. This repositioning of the contactors tends to decrease the period of the vibrator member to counteract the tendency for the period to be increased because of its overall expansion and hence increased length.

In Figure 2 is shown, schematically, a source 32 of constant potential by which the electromagnet comprising cores 24 and 25, coils 26 and 27 and the bar 28 is energized. Coils 26 and 27 are connected in series with the potential source, 32 in such a manner that when a current is passed through them the magnetomotive force induced thereby will be compounded to cause the two ends of the bar 28 to be of opposite polarity.

C011 16 is connected across the potential source 32 in such a manner that current fiowing therethrough will cause pole 33 to be of the same polarity as the extended end of bar 28, and pole 34 to be of like polarity as the opposite end of bar 28. Inasmuch aslike magnetic poles repel, poles 33 and 34 cooperate to urge the bar 28, and hence the vibrator member 21 upwardly to bring the two contactor members 29 and 30 together. when contactors 29 and 30 are together an electric circuit is established permitting current to fiow from the left side. of the energy source 32, Figure 2, through the vibrator member 21, said contactors, circuit leg. 35, coil 17 and circuit leg 36, back to the opposite side of the energy source. (Hereafter the terms fright and left", when used with respect to the term energy source", will be with reference to energy source 32, Figure 2, unless expressly stated to the contrary.)

Coil 16 is connected to the energy source 32 by means of circuit legs 38, 37 and 38. Circuit -17 to cause opposing magnetomotive forces.

polarity of poles 33 and 34. Consequently, poles 33 and 34 will attract the vibrator member, or, more properly, the electromagnet bar 28, to pull the contactor 29away from contactor 30. Thereupon the effect of coil 17 will be consummated; coil 16 will restore the original polarity to poles 33 and 34; and bar 28 will again be repelled by said poles to bring the contactor 29 against contactor 30. Thus, the vibrator member is caused to vibrate, its. vibrating frequency being that of its natural period slightly modified by the various constants of the electric circuit'providing motive means therefor.

While only coil 16' is being energized magnetic flux will be induced in the iron core 10 to build up a voltage potential in the secondary coil 15 in a certain direction. ,When magnetic flux is being built up in coil 17 the magnetic potential in the iron core will be changed and a voltage potential will be built up in coil 15 in the opposite direction. Consequently, if the energy source 32 is of constant potential, there will be an alternating potential maintained across the end terminals of secondary coil 15 while member 21 is vibrating. It is desirable to have the potential across the end terminals of coil 15 reach the same magnitude when the polarity is reversed during each cycle. Toaccomplish this the core 10 and coil 16 will be designed so that when the maximum current is flowing in said coil the core will be saturated with magnetic flux, or, said core will be operating above the knee of its magnetization curve. The flux density in such a core is not materially increased by additional current in the coil thereabout after the saturation point has been attained. Therefore, if both coils 16 and 1'7 operate the core 10 at the knee of its magnetization curve, when they are carrying their maximum of current, the potentials in coil 1-5 due to the magnetic potential set up by 0011 16 and the resultant magnetic potential set up by coils 16 and 17 will be practically equal and opposite, even though the resultant ampere turns are not exactly equal and opposite.

The device, as described, provides a means for changing a constant potential to a desired potential of either lesser or greater magnitude. A greater potential is obtained by placing a greater number of turns in coil 15 than in coil 16, the ratio of the number of turns in the two coils determining, directly, the ratio of the potential across each. This alternating potential developed across coil 15, since it is of balanced form, is readily transformed to direct potential by any conventional type of rectifier. By using a voltage rectifier in connection with this device, a constant potential, of say six volts, may be converted to one hundred and eighty or more volts suitable to be impressed as a bias potential upon the plate of thermionic tubes commonly used in radios. Much higher voltages may be obtained than that mentioned; also, the ratio of the pri-- mary and secondary voltage may be decreased as desired by changing the ratio of turns of the primary and secondary coils.

So far the operation of the device has been described in connection with an operative source of energy of constant potential. The form of the invention shown in Figure 2 operates equally as well when energized from an alternating voltage source. When so energized, its operation is in the manner .now to be described.

First the interrelation of the various parts of the device will be considered at an instantaneous time while the right side of the potential source 32 is positive and the left side is negative. Current will be caused to flow outwardly through circuit leg 39, through electromagnetic coils 26 and 27 and back to the source through leg 40. It will be assumedthat current through coils 26 and 27 in this direction will produce an N pole at the extended end of the vibrator member 21, and an S pole at the opposite end. Properly speaking, the magnetic poles are at the ends of the soft iron electromagnet 28, but the effect is the same as though the vibrator member had been magnetized. For this reason the magnetic poles will be hereafter referred to as being at the ends of the vibrator member 21.

At this same instantaneous time'current will pass outwardly of the right side of the potential source 32 by way of legs 36 and 37, through coil 16 and back to the left side of the energy source. Current passes about the core .n coil 16 in a direction to make an N pole at 33 and an S pole at 34. Thus both poles 33 and 34 repel those of the vibrator to force it upwardly to bring the two contactors 29 and 30 together. Before contactors 29 and 30 are forced together and while magnetic flux is being built up in the core 10 by coil 16 that change in flux will induce a potential in the secondary coil 15 such as will be positive at lead 45 and negative at lead 46. The central lead 47 will be negative with respect to lead 45 and positive with respect to lead 46.

For this device to operate successfully on alternating current the period of the vibrator member .21 must correspond to the frequency of the energy being converted. This is necessary so that as the contactors 29 and. 30 come together the energy source by way of leg 36. This current through coil 17 is in such a direction as to again make poles 33 and 34 .N and S poles respectively. Just as contact members 29 and 30 come together a steady maximum current is established in coil 16 and therefore while there is no change in flux density of the core and while the potential across the secondary coil 15 is zero. The cyclic change in potential of the energy source 32 to make the left side positive and the right side negative takes place while the current in coil 16 is decreasing to zero and while the flux in the core is decreasing to zero because the primary current, and flux caused thereby, are in phase but the primary voltage leads them by ninety degrees. By the time the potential at 32 has reached its greatest negative value, (1. e., when the right side is the most negative with respect to the left side) current will have started to build up in coils 16 and 17, the current in coil 16 being 30 i 17. By increasing the number of turns on coil 45 The device' will operate either from an energy.

member 21, but, since the polarity of poles 33 and 34 remains the same there will be an attraction of the vibrator member by them during the time .the ampere turns of coil 17 exceed the ampere turns of coil 16. This attraction and repulsion oi the vibrator member keeps it vibrating. When, the natural vibrating period of the member 21 is the same as the frequency of the energy source, coil 17.-will be energized during alternating halt cycles to counteract the mag ,netomotlve force 01' coil 16 tending to reverse the flow of fiux in thecore and thus causing periodic impulses oi flux to be built up in the same direction through the secondary coil 15, and hence to cause a pulsating voltage to be built up in said secondary coil.

The amount or energy supplied to secondary coil 15 is in proportion to the ampere turns 0! magnetic energy supplied thereto by coils l6 and 17, the number of amperes required by that coil,

and hence the numberotamperes having their path between contact members 29and 30, may be decreased. In this way the current passing through contacts 29 and 30 may be reduced to such a small amount that e'wear or corrosion of said contacts due to king will be negligible. P Although this device been described in connection witha radio se its application is not to belimited to the field otradio for it will be useiulunder any circumstances requiring the provision of a means for changing either constant or alternating sources of electrical energy to energy or either higher or lower potential.

source 0! constant or alternating potential. When energized from an energy source of constant potential an alternating potential will be developed, and when operating from an energy source of alternating potential a source of energy having an alternating potential will be developed.

There are a number of devices, such as radios, that require for their operation a source of constant potential at a certain voltage. It is always desirable, of course, that such voltage may be obtained from the commercial electric power system, this may be easily done it that system happens to be of alternatingpotential for then ordinary transformers and rectifiers may be used for converting that energy to unidirectional energy at the desired voltage. But a diflerent condition arises when it is desired to convert energy of constant potential to a different potential. It is when this state of aiiairs is encountered that the present device becomes specially useful. The form of the invention shown will operate on either direct or alternating. energy to thus open new fields, in districts whereonly direct current is .available, for certain kinds of equipment that has heretofore been equipped with means for obtaining the desired iorm o't energy only from an alternating energy source. An example of a large fieldhaving only direct current present day clocks having a synchronous motor as a prime-mover therefor may be developed.

What is cla'med as new and is desired to be secured by Letters Patent of the United States is:

1. A converter for producing an alternating potential of regular wave form and comprising an iron core, a coil inductively coupled with said core and disposed to have said potential induced therein, a source of electrical energy, a second coil inductively coupled with said core and being connected to said source 01 energy to provide a component of fiux saturating said core when at its maximum intensity, a third coil inductively coupled with said core and adapted to be connected to said source of energy to induce a component of flux in said core in opposition to the first named component, and means for intermittently connecting said third coil to said source of energy, and in which said third coil is adapted to induce twice the number of lines of flux into said core as is the second named coil.

- 2. A device (for providing from a source of electrical energy of constant potential electricab energy of alternating potential, said device comprising an iron core, a coil inductively arranged about said core and for having said alternating energy induced therein, a second coil about said core and having an electric current of constant intensity passing therethrough to induce a component of'fiux in said core, a third. coil about said core and adapted to be connected to a source of direct current and to generate from such current a component oi. flux in said core oi twice the magnitude and opposite in direction to the first named component of fiux. and means for connecting said third coil to said source of direct 4 third coil about said core and adapted to be .con-

nected to said source of alternating current in a 'manner to induce a component of flux in said core of twice the magnitude of said first component of flux and in opposition thereto, and means for connecting said third coil to said source of alternating current during alternate halt-cycles thereoi'.

4. In a device for converting electrical energy from one form to another, a transformer having an iron core, a coil in said transformer adapted to develop a selected magnetic potential, a second coil in said transformer adapted to develop twice the magneticpotential of the first named coil and having more than twice the number ofturns oi said first coil, and a member adapted to break the electric circuit to the second named coil.

5. In a transformer having an iron core, a primary, and a second primary having twice as many effective ampere turns as said first mentioned primary, a source of energy constantly energizing said first mentioned primary, and means for periodically energizing said second primary from the same source of energy.

6. A device for converting unidirectional electrical energy of one potential into electrical energy of a selected alternating potential, comprising "an iron core adapted to have components of flux induced thereinto, a coil inductively coupled with said core and adapted to have such converted energy induced thereinto by that flux, a. second coil upon said core, said second coil being connected with the source of such unconverted energy to provide a component of such fiux of a magnitude to saturate said core, a third coil inductively coupled with said core, and means for intermittently connecting said third coil to the source of the unconverted energy for energization to establish a second of such components of flux, such second component of flux being of greater intensity than the first component and opposed thereto.

'7. A device for converting electrical energy of either constant or alternating potential into energy of a difierent selected potential of regular wave form and comprising a core adapted to have components of flux induced thereinto, a winding inductively coupled with said core to have the converted energy induced thereinto by such fiux, a second winding upon said core, said second winding being permanently connected with the source of the unconverted energy to induce one of such components of flux in said core, a third winding-upon said core, and means for periodically connecting said third coil with the'source of unconverted energy to provide the other of said components of flux in said core, and the second and third windings being such that the components of flux generated thereby are opposed and the flux generated by the third coilexceeds that of the second.

8.'A device for converting electrical energy of one form into electrical energy of another form and of a selected potential and comprising an iron core and three coils therein and mutually coupled inductively, one of said coils being permanently connected with the source of the un-' converted energy for building up a magneto-mmtive force, a second of said coils being adapted for connection with such unconverted source of energy to build up a magneto-motive force in oppo sition to and greater than the first, the flux resulting from such magneto-motive force passing mutually through said coils to generate the converted energy in the third thereof, and means for periodically connecting the second coil to such source of energy.

9. For converting electrical energy from one form to another of regular wave form and of selected potential, a device comprising an iron core and a plurality of mutually inductive sets of turns of conductor therein, a source of alternating current energy setting up a magnetic potential in one of said sets of turns, means for setting up a magnetic potential of greater intensity in the second of said sets of turns in opposition to the first potential and at alternate periods thereof, and the third of said sets of turns having the converted energy induced thereinto through the combined effect of the magnetic potentials set up in the first two sets.

'rrmonoaa A. com. 

